Platen for photographic printing machines



June 9, 1931. HOPKINS 1,809,238

PLATEN FOR PHOTOGRAPHIC PRINTING MACHINES Filed Dec. 23, 1927 Z Z 5 G i /1 m? v 0 INlfENTOR,

Z1 Z5 'i yqw w .6 M m/ ATTORNEYS.

Patented June 9, 1931 UNITED STATES PATENT OFF-ICE noY s. HOPKINS, or noennsrnn, NEW you, ASSIGNOR r0 EASTMAN KODAK oom- PA Y, or nocnnsrnn, NEW YORK; A coRronA'rIoN OF NEW YORK PLATKN ron PnoroenArHIo PRINTING MACHINES Application filed December 23, 1927. Serial No. 242,150.

This invention relates to photography, and more especially to photographic printing machines. One object of my invention is to provide a platen which will give good contact, that is, one which will press a sheet. of paper into contact with a negative. Another object is to providesuch a'platen with means for compensating for considerable difierences in thickness of the materials used in printing, such as negatives, masks, paper, and the like. Another object is to provlde a platen in which the major rtion of the platen may be transparent an small portions thereof may be opaque, the latter portions being adapted to hold the printing paper. Another object is to provide a platen, the surface of which is normally spaced from the printing panel, and the paper holding members being resilient, and, therefore, adapted to compensate for deviations from a plane surface in both the platen and printing panel, and other objectswill appear hereinafter, the novel features bein pointed out in the claims at the endthereoi. 5 i 2 Coming now to the drawings wherein like reference characters denote like parts throughout: i

Fig. 1. is a fragmentary sectional view of a printing machine having a platen constructed in accordance with and embodying a {preferred form of my invention;

Fig. 2 is an enlarged fragmentary bottom plan view of a portion of a platen plate Fig. 3 is a fragmentary sectionalview of a portion of a printing panel and platen plate; v

Fig. 4 is an enlarged detail section of an other type of resilient contact member;

Fig. 5 is a fragmentary section illustrating another embodiment of m invention. 7

In certain classes of p otogra hie printing the: thickness of photographic material upon the printin siderable degree,% a negative guide or paper guide of considerable thickness may be used, so that in order to provide good contact it is desirable to have portions of the platen compressed to a greater degree than otherportions.

' As illustrated in 1, the printingmachine may comprise a housing in whiCh panel may vary to a conofthe platen plate which or instance, a mask having there is'a lamp 2 mounted in a reflector 3 beneath a printing panel 4 carried by a rabbet 5 in the slanting front 6 of the cabinet A platen 7 may be carried by a frame consisting of two parts 8 and 9 hinged together at 1 0,section 8 being hinged at 11 to a yoke 12. The printing panel 4 and platen 7 constitute a printing frame adapted to hold a sheet of photographic paper in contact with a negative during the printing operation. I

I prefer to mount the yoke 12 resiliently, and in the present embodiment the yoke 12 includes a cross bar 13 resiliently supported by the springs 14, there being a set screw 15 by which the extent of movement is limited.

I I also prefer to provide a coil spring 16 tending to turn platen section 9 about its hingelO in the direction shown by the arrow. Handle 17 carried by lugs 18 of the platen frame 19 is also provided for moving the platen to and from the printing panel.

As thus far described the printing machine is merely a typical one which has been selected as suitable for illustrating my invention. In order to provide a platen through which the printing operation may be watched and which will have an extremely resilient contact with the photographic material, the structure hereinafter described may be employed. I prefer to provide transparent platen plates 7 of tinted or colored pyroxylin, the tint being such that the operator will not be blinded by looking through the platen at the printing light. The pyroxylin plates are provided with a series of apertures 19., and it is desirable to arrange the rows of apertures at an angle to the edges 20 of the platen plates. Into each aperture a resilient contact member designated broadly by 21 may be placed so that a series of relatively small resilient projections are provided on that side faces the printing panel. t

As shown in Fig. 3, thecontacting members 21 may consist of a shank portion 22 and a head 23 which is provided with a shoulder 24 between the head and the shank. The shank closely fits into the platenapertures 19, and if desired may be firmly held therein by cement. Th s it wi lbe seen th t the m j r j 5 the head is brought into engagement with. the

portion of the platen is transparent so that dodging may be Watched throughthe platen during the printing operation, as a comparatively small portion of the platen is covered by the resilient contact members.

With this type of construction, as is shown in Fig. 3, firm and even pressure is applied at close intervals all over the printing paper orupon any material laid on the printing panel. In Fig. 3 I have shown a negative N on which is laid a sheet of printing paper P,

' there being also provided a guide member G for locating the paper such as is commonly usedin double printing; The contact members 210 have been flattened out by the pres. sure applied to these platen areas, and con- 7 tacts 21a have been compressed only to a very face of'a sheet of dash linesat P.

slight extent. Since these contacts are closely spaced the paper is held flat. V

I have found that the most satisfactory results can be obtained by arranging the'con- V tact members in rows at an angle to the edges of the platen because ordinarily a print is made with the edges of the print substantiallyparallelto the edges of the platen and by arranging the rows, as shown, for instance, in Fig. 2, the contacting members will be more or less irregularly disposed over the surpaper indicated in dot and 7 While I have illustrated the resilient contacts as being evenly spaced this is not necessary so long as they are arranged close enough to prevent the paper from bendingupwardly thus losing contact with the negative. It

is, of course, useful to separate thecontacts V as far as possible since this leaves a larger area of the platen transparent, and the printat 192 so that a head193 will be formed on the lfly in place without the use of cement. As

ingoperation' may be readily viewed. If desired, the contacts may be carried upon an opaque platen in which case they may be arranged as closely as desired, it only being necessary to leavesufiicient room between them for expansion under pressure, such a structure Wlll be "scribed."

hereinafter more fully decast into apertures 191 which are countersunk shan'k'19 of the contact, thus holding it firmshown in this figure, the head 195' isin its I normal'print contacting position. lVhen under normal pressure onlya small portion'of j .printingj'papen When, however, the contact strikes a' projection such as a paper guide G I .the head 195 may be compressed and the shape will'c'hange, asindicated by the dot and dash line195CQ' 3'1 1 r I prefer'to-forin the contact members of;

soft rubber, although any other resilient ma- 'terial' may be equally suitable, I, V 7 v shown in Fig. 5, if an opaque platen plate 27 is used the resilient contacts may be If desired, the resilient contacts 21 may be made in the form of a sheet 28 on which the contacts 29 are integrally formed. This sheet may be cemented upon plate 27 or may be fastened to it in any desired manner, such as by vulcanizing. While such a platen does not have the advantage ofbeing translucent, like the embodiment shown in the other figures,- I have found a platen resiliently press- 7 ing over relatively small areas of the printing paper will give more uniform good contact under varying condltions than other structures which I am familiar with.

In both the embodiments illustrated the platen, designated broadly as 117 is provided with an irregular or roughened surface only "a relatively small area of which contacts with the printing paper, the major'portion (plate 7 or. 27 of the platen being spaced from the point of contact. This has the advantage of ing panel or platen is perfectly flat, because the resiliency of the protuberances automatically cares for any such variations between these parts. This is useful because inflarge sizes plate glass rarely has a true plane surface, and even when it has it is dilficult to make a platen which Will accurately fit the printing panel With the resilient protuberances good contact is'secured even though the printing panel and platen are considerably out of parallel; I 7

Most of the force necessary tooperate the usual type of printer is used in an attemptto physically press the platen upon the printing panel so tightly that goodcontact will result.

VVith the above described very resilient spaced protuberances the major portion of the platen is spaced from the panel and only a minimum amount of force isjnecesary to operate the platen as only the resilient protuberances are compressed, and these only to a slight degree. 7

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is 7 I 1. In a printing device, the combination with'a printing panel, of a platen mounted to move. to and from'the panel, and means including a substantially fiat transparent platen surface having projections thereon,said pro- V jections being made'of resilient material, and

forming contacts adapted to engage printing material laid on the panel. r V

2. In a printing device the combination with a printing panel, of a platen mounted to move to and from said panel, said platen in cluding a substantially flat plate having a series of apertures therein, and a plurality of contact members mounted in the apertures.

3. In a printing device the combination with a printing panel, of a platen mounted to move to and from said panel, said platen including a substantially fiat light transmitting plate having a series of apertures therein, and a plurality of contact members mounted in the apertures.

4. In a printing device and combination with a printing panel, of a platen mounted to move to and from said panel, said platen including a substantially fiat light transmitting plate having a series of apertures therein, and a plurality of resilient contact members mounted therein. I

5. In a printing device the combination with a printing panel, of a platen movable to to and from the panel, said platen including an apertured plate, contact members having enlarged heads on shanks mounted on the plate by means of the shanks extending into the apertures, said enlarged heads projecting from the platen toward the printing panel.

6. In a printing device the combination with a printing panel, of a platen movable to and from the panel, said platen including an apertured plate, rubber contact members supported in the apertured plate, said rubber contact members having enlarged heads.

7. In a printing device the combination with a printing panel, of a-platen movable to and from the panel, said platen including a flat plate and a contacting face of relatively small spaced rubber protuberances adapted to hold a sheet of paper flat spaced from the flat plate.

8. In a printing device the combination with a rinting panel, of a platen movable to and rom the panel, said platen including a contacting face of relatively small resilient protuberances arranged in rows at an angle to the edges of the platen.

9. In a printing device the combination with a printing machine, of a platen mounted to move to and from the platen, said platen including an apertured plate, a plug, a head and shank separated by a shoulder on the plug, said plug having the shank engaged in the aperture with the head projecting from the plate, the shoulder preventing the plug from being pushed through the aperture, said head projecting from the platen toward the printing panel.

10. In a printing device the combination with a printing machine, of a platen mounted to move to and from the platen, said platen including an apertured plate, a plug of resilient material, a head and shank separated by a shoulder on the plug, said plug having the shank engaged in the aperture with the head projecting from the plate, the shoulder preventing the plug from being pushed through the aperture, said head projecting from the platen toward the printing panel.

11. In a printing device, the combination with a printing panel of a platen movably mounted with respect thereto, said platen having an irregular contacting surface, a l 

